| 1. |
- Fan, Jieyu, et al.
(författare)
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Analyzing and Optimizing the Emission Impact of Intersection Signal Control in Mixed Traffic
- 2023
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Ingår i: SUSTAINABILITY. - 2071-1050. ; 15:22
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Tidskriftsartikel (refereegranskat)abstract
- Signalized intersections are one of the typical bottlenecks in urban transport systems that have reduced speeds and which have substantial vehicle emissions. This study aims to analyze and optimize the impacts of signal control on the emissions of mixed traffic flow (CO, HC, and NOx) containing both heavy- and light-duty vehicles at urban intersections, leveraging high-resolution field emission data. An OBEAS-3000 (Manufacturer: Xiamen Tongchuang Inspection Technology Co., Ltd., Xiamen, China.) vehicle emission testing device was used to collect microscopic operating characteristics and instantaneous emission data of different vehicle types (light- and heavy-duty vehicles) under different operating conditions. Based on the collected data, the VSP (Vehicle Specific Power) model combined with the VISSIM traffic simulation platform was used to quantitatively analyze the impact of signal control on traffic emissions. Heavy-duty vehicles contribute to most of the emissions regardless of the low proportion in the traffic flows. Afterward, a model is proposed for determining the optimal signal control at an intersection for a specific percentage of heavy-duty vehicles based on the conversion of emission factors of different types of vehicles. Signal control is also optimized based on conventional signal timing, and vehicle emissions are calculated. In the empirical analysis, the changes in CO, HC, and NOx emissions of light- and heavy-duty vehicles before and after conventional signal control optimization are quantified and compared. After the signal control optimization, the CO, HC, and NOx emissions of heavy-duty vehicles were reduced. The CO and HC emissions of light-duty vehicles were reduced, but the NOx emissions of light-duty vehicles remained unchanged. The emissions of vehicles after optimized signal control based on vehicle conversion factors are reduced more significantly than those after conventional optimized signal control. This study provides a scientific basis for developing traffic management measures for energy saving and emission reduction in transport systems with mixed traffic.
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| 2. |
- Fan, Jieyu, et al.
(författare)
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Emission impacts of left-turn lane on light-heavy-duty mixed traffic in signalized intersections: Optimization and empirical analysis
- 2023
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Ingår i: Heliyon. - 2405-8440. ; 9:5
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Tidskriftsartikel (refereegranskat)abstract
- Reducing emissions from the transport sector is one of the crucial countermeasures for climate action. This study focuses on the optimization and emission analysis regarding the impacts of left-turn lanes on the emissions of mixed traffic flow (CO, HC, and NOx) with both heavy-duty vehicles (HDV) and light-duty vehicles (LDV) at urban intersections, combining high-resolution field emission data and simulation tools. Based on high-precision field emission data collected by Portable OBEAS-3000, this study first develops instantaneous emission models for HDV and LDV under various operating conditions. Then, a tailored model is formulated to determine the optimal left-lane length for mixed traffic. Afterward, we empirically validate the model and analyze the effect of the left-turn lane (before and after optimization) on the emissions at the intersections using the established emission models and VISSIM simulations. The proposed method can reduce CO, HC, and NOx emissions crossing intersections by around 30% compared to the original scenario. The proposed method significantly reduces average traffic delays after optimization by 16.67% (North), 21.09% (South), 14.61% (West), and 2.68% (East) in different entrance directions. The maximum queue lengths decrease by 79.42%, 39.09%, and 37.02% in different directions. Even though HDVs account for only a minor traffic volume, they contribute the most to CO, HC, and NOx emissions at the intersection. The optimality of the proposed method is validated through an enumeration process. Overall, the method provides useful guidance and design methods for traffic designers to alleviate traffic congestion and emissions at urban intersections by strengthening left-turn lanes and improving traffic efficiency.
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| 3. |
- Fan, Jieyu, et al.
(författare)
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Evaluating the Impact of Signal Control on Emissions at Intersections
- 2022
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Ingår i: Smart Innovation, Systems and Technologies. - Singapore : Springer Nature Singapore. - 2190-3026 .- 2190-3018. ; 304 SIST, s. 104-111
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Konferensbidrag (refereegranskat)abstract
- Transport emission has become an increasingly serious problem, and it is an urgent issue in sustainable transport. In this study, by constructing traffic emission models for different vehicle types and operating conditions, the changes in CO, HC, and NOx emissions of light-duty and heavy-duty vehicles before and after signal control optimization were quantified based on VISSIM simulation. The OBEAS-3000 vehicle emission testing device was used to collect data on the micro-operational characteristics of different vehicles under different operating conditions as well as traffic emission data. Based on the data collected, the VSP (Vehicle Specific Power) model combined with the VISSIM traffic simulation platform was used to calculate the emissions of light and heavy vehicles in the mixed traffic flow before and after intersection signal optimization. It is known from the study that signal control optimization has a greater impact on heavy vehicles than on light vehicles. Emissions of CO, HC, and NOx from heavy vehicles and light vehicles are all reduced, but NOx emissions from light vehicles remain largely unchanged. The research results reveal the emission patterns of light and heavy vehicles in different micro-operating conditions and establish a traffic emission model. It provides a theoretical basis for accurate traffic emission analysis and traffic flow optimization, as well as a scientific basis for the formulation of traffic management measures and emission reduction in large city transport systems.
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| 4. |
- Gao, Kun, 1993, et al.
(författare)
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How to Model the Influence of In-vehicle Crowding on Travel Behavior: A Comparison Among Moderation, Independent Variable and Interaction
- 2020
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Ingår i: Smart Innovation, Systems and Technologies. - Singapore : Springer Singapore. - 2190-3026 .- 2190-3018. ; 185, s. 41-52
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Konferensbidrag (refereegranskat)abstract
- Accurate modeling of travel choice behavior is crucial for effective transport demand forecasting, management and planning. This study tries to shed light on the appropriate modeling approach concerning the influences of in-vehicle crowding on mode choice behavior in the multimodal network. Stated preference surveys covering four commuting transport modes and four influencing factors are conducted to collect empirical behavior data. Three modeling methods, treating the in-vehicle crowding as a moderator of perceived travel time, as an independent variable and by incorporating interaction effect, are empirically compared. The result indicates that there is a bidirectional interaction between travel time and in-vehicle crowding. The influence of in-vehicle crowding increases with increasing travel time and vice versa. Considering crowding as an independent variable and taking the effects of travel time on the perception of in-vehicle crowding are the best ways to depict the overall influences of in-vehicle crowding. The sensitivity analysis shows that increasing the cost of using car is comparatively effective for reducing car usage. Shortening the travel time of public transit and improving service quality such as travel time reliability and in-vehicle crowding are more useful in attracting car users as compared to reduction in the cost of public transit. The results provide insights into travelers’ behavior in the multimodal network and could support scientific transport management and planning.
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| 5. |
- Ji, Xinyu, et al.
(författare)
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Epigenetic–smoking interaction reveals histologically heterogeneous effects of TRIM27 DNA methylation on overall survival among early-stage NSCLC patients
- 2020
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Ingår i: Molecular Oncology. - : Wiley. - 1574-7891 .- 1878-0261. ; 14:11, s. 2759-2774
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Tidskriftsartikel (refereegranskat)abstract
- Tripartite motif containing 27 (TRIM27) is highly expressed in lung cancer, including non-small-cell lung cancer (NSCLC). Here, we profiled DNA methylation of lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC) tumours from 613 early-stage NSCLC patients and evaluated associations between CpG methylation of TRIM27 and overall survival. Significant CpG probes were confirmed in 617 samples from The Cancer Genome Atlas. The methylation of the CpG probe cg05293407TRIM27 was significantly associated with overall survival in patients with LUSC (HR = 1.65, 95% CI: 1.30–2.09, P = 4.52 × 10−5), but not in patients with LUAD (HR = 1.08, 95% CI: 0.87–1.33, P = 0.493). As incidence of LUSC is associated with higher smoking intensity compared to LUAD, we investigated whether smoking intensity impacted on the prognostic effect of cg05293407TRIM27 methylation in NSCLC. LUSC patients had a higher average pack-year of smoking (37.49LUAD vs 54.79LUSC, P = 1.03 × 10−19) and included a higher proportion of current smokers than LUAD patients (28.24%LUAD vs 34.09%LUSC, P = 0.037). cg05293407TRIM27 was significantly associated with overall survival only in NSCLC patients with medium–high pack-year of smoking (HR = 1.58, 95% CI: 1.26–1.96, P = 5.25 × 10−5). We conclude that cg05293407TRIM27 methylation is a potential predictor of LUSC prognosis, and smoking intensity may impact on its prognostic value across the various types of NSCLC.
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| 6. |
- Peci, Gentrina, et al.
(författare)
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Usage Pattern Analysis of e-scooter Sharing System: A Case Study in Gothenburg, Sweden
- 2022
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Ingår i: Smart Innovation, Systems and Technologies. - Singapore : Springer Nature Singapore. - 2190-3026 .- 2190-3018. ; 304 SIST, s. 123-132
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Konferensbidrag (refereegranskat)abstract
- Swedish cities are embracing shared micro-mobility systems (SMMS) such as e-scooters sharing systems to promote sustainable travel behavior in urban contexts with corresponding infrastructure planning. SMMS is associated with various social, environmental, and economic benefits, as well as providing solutions for the first- and the last-mile problem of using public transit. This study analyzes the usage patterns of e-scooter systems, based on the scooter operation data of VOI company in Gothenburg, Sweden. The used data cover the transaction data of two and half months during the summer and include over five hundred thousand valid trip records. The result shows that most trips travel a distance between 0.5–1.8 km while the duration lasts between 4–7 min. Fridays and Saturdays are the most popular days while Sunday is the least popular day. The number of trips on Sundays decreases by about 60% compared to Fridays and Saturdays. Moreover, the e-scooters are used to varying degrees in the different areas of Gothenburg. The e-scooters are used at a much higher extent in central Gothenburg compared to areas outside the city center. This can be due to several different factors such as location, land use, and accessibility. Lastly, the results show that the e-scooters are not primarily used for commuting but rather for leisure, which can be seen in the average distance and duration of the entire zone as well as the temporal distribution.
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